Microalgae Chlorella sp. green algae is a plant which has many benefits. One of the chemical compounds in microalgae is steroid compounds. The purpose of this research is to determine the antioxidant activity of steroid compounds ethyl acetate fraction of microalgae Chlorella sp. results with KLTP separation and identification with UV-Vis spectrophotometer.

Microalgae Chlorella sp. obtained from cultivation using Sprouts Extract Media (MET). Dry biomass of microalgae produced later in the maceration using methanol. The crude extract of maceration results in hydrolysis catalyst HCl and partitioned with ethyl acetate. The results obtained in separate partitions using Preparative TLC with solvent n-hexane and ethyl acetate ratio of 4: 1. steroid derived isolates tested antioxidant activity with DPPH and identified with UV-Vis spectrophotometer.

The results of this research show that the dry biomass of microalgae is 30 grams. Results of measuring the water content is 10.15%. Randemen maceration results obtained by 21.8926%. Results randemen hydrolyzate obtained is equal to 80.95%. The results of the separation of the heavy steroids is 2 mg KLTP. And test results obtained antioxidant activity of steroid compounds EC50 values of 77.78 ppm. The results of the identification of steroid compounds obtained maximum wavelength of 204 nm.